In many baking processes, a receiver is located immediately above a mixer for mixing a batch of dry ingredients in preparation for dumping into the mixer. Typically, the major ingredient is flour which is "pressure blown" into the mixer by a pressurized air conveyor system. In most installations, there are several mixers positioned about the plant, all of which require large quantities of flour and which are all interconnected into a single pressure blow system in a continuous loop or ring. The pneumatic conveyor tube which carries the flour in this pressure blow system is connected to a bottom diverter valve situated at the top of each receiver, the bottom diverter valve being movable from a first position which permits flour to be blown past the receiver onto the next receiver in line, and a second position which diverts the flour down into the receiver and back out into the downstream tube in order to maintain pressure connection throughout the system. Also typically, the receiver is supported by load cells or the like such that the amount of flour blown into the receiver may be measured by weight. As the flour is transferred in a pressure environment, a substantial amount of dust is created within the system but, as the system is a closed system, this dust is easily handled without problem by a single bag house or dust bin located back at the main bulk flour supply bin.
In addition to the flour ingredient which is a major ingredient, there are other ingredients which are typically added in manually to the receiver. For example, a typical batch might include 400 lbs. of flour, 50 lbs. of so-called minors, and 20 lbs. of so-called micros. As mentioned, these minors and micros are typically manually dumped into the receiver to complete the preparation of each batch.
Because these receivers are elevated above mixers which are designed to mix up 2,000 lb. doughs, in many installations the receiver virtually eliminates any additional head room in the plant. Thus, it becomes very difficult to modify the flour conveyor or pressure blow system or otherwise consider automating the addition of minors and micros to a receiver. Additionally, the pressure blowing of minors and micros into the same receivers could potentially contaminate the continuous loop flour pressure blow system with the minor/micro ingredients which, of course, would be highly undesirable. Therefore, the inventors herein were faced with significant problems in attempting to automate the addition of minors and micros to the receiver for the baking process.
In order to solve these and other problems in the prior art, and to achieve an automation which could be successfully implemented for existing plant installations, the inventors herein have designed several alternate pressure blow bulk transfer arrangements which require only minor modification to the existing flour pressure blow system and which also accommodates the automatic pressure blowing of minors and micros into the same receivers as are used with the old prior art manual process. For each of these arrangements, this includes adding a bin vent or bag house or other dust collection arrangement at each receiver which is also supported by load cells. In the first arrangement, the original flour ring pressure blow system is teed into a new minor/micro pressure blow tube which feeds the bottom diverter valve. A second tee connection in the flour pressure blow system upstream from the first tee connection bypasses the receiver for routing to the next receiver in line. Thus, flour may be blown into the receiver and the bottom diverter valve used to vent the pressure blow system into the bin vent where the flour dust is collected and the system is vented to atmosphere. In a typical "blow", approximately 8% of the dry material transferred to the receiver will be in the form of dust which passes through the receiver and is collected as dust in the bin vent. However, as both the receiver and bin vent are supported by the same assembly from load cells, the total dry material weight may be accurately ascertained. As with flour, minors and micros may be blown into the receiver with the bottom diverter valve used to vent the dust from the receiver into the same bin vent where the minor/micro dust is collected as well. A screw auger or the like at the bottom of the bin vent is conveniently used to auger the ingredient dust back into the receiver for dumping into the mixer.
In a second arrangement, a third tee-valve and a Y-connection are added downstream of the bottom diverter valve at each receiver. With this arrangement, not only are the same advantages provided as with the first arrangement, but it is also possible to convey flour and divert the dust away from the dust bin back into the flour pressure blow system as is done in the original flour ring. In this mode, flour is collected in the receiver only and no flour dust accumulates in the dust bin. If desired, selected ingredients of the minors/micros may then be blown solely into the dust bin and collected there for later addition to the baking process. While the same feature may be substantially provided in the first arrangement, as the flour blow collects flour dust in the dust bin, a small but not insubstantial quantity of flour dust is also withheld from the early part of the mixing process which, in some formulations, might present a problem. With this second arrangement, all of the measured flour may be added at the beginning of the mixing process and only selected minor/micro ingredients withheld for later addition. Therefore, with this second arrangement, even greater control over the mixing process may be attained.
In still a third arrangement, the original flour ring remains intact and a second minor/micro pressure blow system includes its own bottom diverter valve accessing the receiver and a dust bin. This arrangement provides the same advantages as explained above in connection with the second arrangement and does it without the use of any tee-valves or junctions. Instead, only a single bottom diverter valve need be added, along with a dust bin, at each receiver. This arrangement also provides the convenient optional feature mentioned above for the second arrangement. Some ingredients, such as salt, would desirably be added at an advanced stage of the mixing process and after the pre-mix has been dumped into the mixer. For these situations, the bottom diverter valve could be positioned to permit the salt (or other ingredients) to be blown past the receiver and directly into the bin vent. Then, at the advanced mixing time, the screw auger could be used to auger the salt into the mixer. In this manner, the automated system may accommodate the addition of selected ingredients at advanced stages of the mixing step.
While the principal advantages and features of the present invention have been mentioned above, a greater understanding may be attained by referring to the drawing and description of the preferred embodiment which follow.